The Aeropress makes something very similar to drip coffee, if you dilute it as you describe. It is not really right to call the shot it produces "espresso". It's really more like very very strong regular coffee. Therefore when you dilute it, you get regular coffee, not an americano.
That said, if you pay attention to variables like grind, timing, and temperature, it will probably taste better than most drip coffee.
Posted Wed Oct 26, 2011, 6:13pm Subject: Re: Aerobie Aeropress
I make a cup from the AP every morning. I weigh mine, about a 16 to 1 ratio, 20 grms of coffee grind to 320 grms of water. I let it steep about 1 1/2 minutes, then push what's left through the filter. Nice cup, I think.
I pour til it fills up, stir and pour again until all the water is in the "syringe".
Posted Thu Oct 27, 2011, 5:10am Subject: Re: Aerobie Aeropress
I've experimented with a wide range of brewing parameters now, and have found a couple of neat things:
Brewing inverted is the way to go - you get to control the contact time.
The AP has some (maybe purposeful, maybe serendipitous) built-in features that guard against over extraction, but can make it underextract if you're not careful.
First off: increase the end yield by ambient-temp pre-infusion of same ml of water as coffee grams. This does a few things: -it pre-soaks the cellulose of the grinds so brew water isn't part of the coffee absorption. -it suppresses the bloom, -it helps a bunch of the CO2 out of the grounds (so they don't saturate the brew water, changing the acidity during rapid changes of temperature in solution - in fact, this is tied in with bloom suppression, but important enough that bloom suppression has a dual purpose).
Pre infusing with a 1:1 ratio makes a thick almost-paste, stir it up thoroughly. There's not enough water to affect the brew temperature, so don't worry about that, and even if you use hot water, the temperature of the paste drops so quickly (to about 135°F) it really won't start the extraction.
Second: with initial brew ratios of around 16-20%, the brew temperatures drop significantly faster than a french press. 200°F brew water, drops to 190°F in the grounds slurry immediately after first pour, then drops to about 180°F in the next 45 seconds, and by 2 minutes will be around 175°F. Start with 170°, and the brew slurry will be about 30°F lower at 3 minutes. Extraction begins to stall out much below 180°F. So, thermally, it has a built-in stop for extraction - much like cupping (where the extraction pretty much stops as the brew slurry drops in temperature - that's how you can have a half-hour cupping session with the grounds in contact with the coffee the entire time yet the coffee still can taste pretty darn good as it cools).
I've done many blind taste sessions using brew ratios from 5% up to more than 30% - diluted AP coffee (for me) is indistinguishable IF PROPERLY EXTRACTED from straight strength coffee. Changes in taste come from variations in extraction.
This means the method of extraction controls extraction, the brew ratio controls strength, and the AP allows fairly independent control over these up to about 20% brew ratio.
My recipe: Grind ~500micron (Ditting 5, 15-18 Hario MMS modified declicks, Baratza 20ish). for 350 ml at the end (size of my cup) at about 1.25% strength: 22g coffee. 200°F brew water, brew ratio around 15%-18% (it doesn't really matter, really. remember, extraction is extraction) or about 120-145ml. 20ish g of room temperature water - add to grounds and make a pre-infusion paste. water hardness ~130-170 ppm
Brew inverted, contact time about 2:00, flip and press.
I stir to make sure the grounds are saturated and well integrated - vigorously around 30 seconds, a second time about 1 minute. Otherwise, fresh roasted coffee, even though the bloom is suppressed, will still have a tendency to float at the top of the brew slurry from residual off-gas and can contribute to underextraction, sometimes severe.
At the end of the press, I squeeze every bit I can out of the grounds. People think that this gets more bitters out of the grounds, but in my experience it's just not the case. The coffee in the grounds is already extracted, and once you've pressed the coffee, those last 10 grams are just wasted if you don't press them. The water absorbed in the grounds consists of water absorbed and un-pressable (like a paper towel where you can't wring it 100% dry no matter how hard you wring or press it - the water is absorbed into the cellulose structure of the fibers and only dehydration can get it out), and coffee that is the strength that's in the cup - if you don't press it, those precious drops go to waste.
This method yields approximately the same grams of coffee as the brew water (because the absorption is already covered with the pre-infusion).
Either way, if you did this right, you end up with about 20% extraction or 4.4g of total dissolved coffee solids in the cup. Dilute (top off with hot water) to 350ml (hey - that's pretty close to 12 ounces!) and you have a top notch cup of coffee near-worthy of gold cup standards.
The low end of contact time is 30 seconds - less and you underextract.
I've played around with 5, 8 and even "to cool" contact times, this upper end is only about 22.5% extraction - on the heavy side but not crazy Turkish coffee overextraction. Some extremely bright coffees and even some of the fruity coffees (think central am's for the former, central af's for the latter) actually do well close to overextraction.
If the brew temp is 205°F, overextraction may come on around 3-4 minutes contact time, and if you use IMMEDIATELY off boil or superheated microwave water (latter can be as high as 214°F), technical overextraction >22% might be around 2-2 1/2 minutes contact time.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
au4life_rz Senior Member Joined: 28 Oct 2011 Posts: 3 Expertise: I love coffee
Posted Fri Oct 28, 2011, 7:37am Subject: Re: Aerobie Aeropress
AlanAdler Said:
Hi Rich,
Every study that I'm aware of has reported that paper filtering virtually eliminates the harmful lipids. You'll see that when you read my attachment.
I also sent two AeroPresses to The Department of Agrotechnology and Food Science, Wageningen University in the Netherlands. They conducted the same tests on the AeroPress brew which they had conducted on all of the other brewing methods in their prior study which I quoted in the attachment.
They found that the AeroPress brew had similar levels of lipids as paper filtered drip brew. This seems reasonable to me. We use the same oxygen bleached paper that is used in high-quality cone filters.
The exact AeroPress levels were:
For a new filter: Cafestol = 0.122 mg Kahweol = 0.125 mg
At my request they also used the same filter for ten pressings without washing. The lipid levels gradually rose with each pressing to the following after the tenth pressing: Cafestol = 0.36 mg Kahweol = 0.37 mg
They then washed the same filter and pressed an eleventh time. The lipid levels were: Cafestol = 0.20 mg Kahweol = 0.22 mg
All of the above levels are for a serving of 150 ml Americano or an undiluted single-scoop "AeroPresso". These serving sizes are identical to those used in their prior report.
This is wonderful information, (thanks), but it would be great if the document and studies showed results for the Aeropress right beside the other brewing methods, (so as to ensure that it's an apples to apples comparison). I basically want to know the normalized amounts of "bad" elements I get in an average 8 ounce cup of coffee for each method. Even though the Aeropress uses paper filters, I could see the pressure impacting the amount of ditherpenes (sp?) contained in the resulting brew. I hope that there are more studies done showing all methods side by side.
jpender Senior Member Joined: 11 Jul 2011 Posts: 406 Location: California Expertise: I like coffee
Grinder: Kyocera CM-50 Vac Pot: S/S Moka Pot Drip: Aeropress
Posted Fri Oct 28, 2011, 8:06am Subject: Re: Aerobie Aeropress
Netphilosopher Said:
-it helps a bunch of the CO2 out of the grounds (so they don't saturate the brew water, changing the acidity during rapid changes of temperature in solution
I wouldn't say it reduces acidity per se. I think it basically makes slightly-before-peak coffee taste less "unrested". I hope that makes sense - everyone talks about "resting" freshly roasted coffee, and there's lots of hypotheses about why, but I've noticed over several hundred cups and many roasts that this rest and development period (call it "maturation") to peak flavor seems to coincide with the CRAZY bloom that comes off of unrested brewed coffee.
To me, unrested coffee when brewed tastes like it has fizzle, zing, or a buzzy brightness that I wouldn't immediately classify as "acidic". I find this tends to interfere with my ability to sense/taste the rest of the flavor profile. It's like porn, I can't define it, but I know it when I see (taste) it. LOL
Pre-infusion supresses the bloom, and also goes a long way in mitigating pre-peak (partially unrested) freshly roasted coffee.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
jpender Senior Member Joined: 11 Jul 2011 Posts: 406 Location: California Expertise: I like coffee
Grinder: Kyocera CM-50 Vac Pot: S/S Moka Pot Drip: Aeropress
Posted Fri Oct 28, 2011, 10:01am Subject: Re: Aerobie Aeropress
Thanks for the explanation. It sounds like this matters most to people who roast their own. I don't (yet) and the beans I buy are usually roasted 2-5 days prior. While I have noticed that more recently roasted beans have more bloom I don't think I'm seeing the huge blooms you're talking about.
Another question (or three):
Netphilosopher Said:
increase the end yield by ambient-temp pre-infusion of same ml of water as coffee grams. This does a few things: -it pre-soaks the cellulose of the grinds so brew water isn't part of the coffee absorption.
Why does it matter that the pre-infusion water is not part of the brew water? Isn't it true that all the water is ultimately mixed anyways? And how does pre-infusion lead to increased yield?
paulbel Senior Member Joined: 26 Apr 2008 Posts: 127 Location: Vancouver, BC, Canada Expertise: I love coffee
Espresso: aeropress Grinder: conical burr (cuisinart) Drip: sometimes
Posted Fri Oct 28, 2011, 10:53am Subject: Re: Aerobie Aeropress
au4life_rz,
Unfortunately, Alan Alder, inventor of the Aeropress, no longer participates in this forum (long story, which you can pick up if you read back into this forum)
You could try to follow up with Alan (or Alex Tennant) by writing to aerobie@aerobie.com
Posted Sun Oct 30, 2011, 9:34am Subject: Re: Aerobie Aeropress
jpender Said:
...Why does it matter that the pre-infusion water is not part of the brew water? Isn't it true that all the water is ultimately mixed anyways? And how does pre-infusion lead to increased yield?
The quick answer: that extra 10g is like adding (mass-wise) 10g to your brew water - you'll get this in the cup at the end.
If you use 6 oz (177g) of brew water and 10g of coffee, the breakdown looks like this:
177g Water 10g coffee 187g of brewing coffee slurry.
You will end up with about 160g of coffee after you're done with extraction, which actually consists of about 158g of water and 2g of dissolved solids, or around 5.4 oz.
If you pre-infuse 1 to 1:
177g Water 10g coffee 10g pre infusion water 197g of brewing coffee slurry.
You will end up with about 170g of coffee after you're done with extraction, which actually consists of about 168g of water and 2g+ a smidge of dissolved solids, or around 5.7 oz.
So far so good:
After extraction, if you gravity drain the coffee (like in a drip maker, or if you're cupping coffee and scooping out grounds) the coffee grounds leftover consists of about 8g of grounds, and about 20g of water. You can measure this experimentally by weighing the coffee grounds leftover, it will be about 28g give or take.
These grounds actually consist of water absorbed in the cellulose structure of the grounds - it doesn't participate as a solvent - about 10g of the 20g are exactly that - stuck in the ground structures of the bean and unavailable to get anything into solution. It doesn't mean this is unimportant - it softens and opens the structure of the ground coffee so that water can get in and do its work as a solvent. And the grounds also contain the other 10g is actually coffee, consisting of 9.875g of water with 0.125g of dissolved solids - not enough to matter in the end cup, but it's what makes up the remaining wet grounds.
IF you pre-infuse with 10g of water, the majority of this gets absorbed in the structure of the coffee, opening and soaking the grounds. This opening and soaking allows trapped CO2 to get out (the primary reason for the bloom), but then it's stuck in the cellulose structure of the grounds. When you go to make coffee, another 10g of your brew water participates as a solvent and is able to get through to the end cup.
Incidentally, the coffee that's trapped in the coffee grounds will be less if you put it in an aeropress and squeeze any remaining coffee out. Lets pretend you do exactly that (like I do with my Aeropress every morning) and sqeeze the crap out of the coffee, getting every last drop out.
Then the puck will weigh about 21g or so, instead of 28 - and you get another 9g of coffee (same strength, etc.) in your cup. If you take that coffee grounds puck and try and get any more out - you might get maybe another gram, but at that point you can't really squeeze anything else out - like the cloth that you can't wring 100% dry.
I've gotten a couple of emails that ask why this is different than just adding another 10g to the brew water - it's quite different. Dump hot water into dry fresh grounds creates the bloom which can mechanically (not necessarily chemically) interfere with extraction because the bubbles keep solvent water away from the grounds. I think that this is why cupping fresh grounds (read the cupping protocols - roasted less than 24 hours prior to cupping) doesn't overextract - the bloom prevents crazy hot water from getting to 100% of the grounds. You don't break the crust for a few minutes after pouring the brew water in. During these minutes, as the grounds begin to soak up water, some of the water is doing the cellulose absorption, and the grounds gradually get into the brew water over a period of time. However by then the temperature has dropped below severe overextraction temperatures.
Props to Jerry (jkalpin) for his hints on bloom interfering with extraction. Caused me to really think further about the extraction process and the issues that bloom poses to a low contact time brew method like the Aeropress.
As I get into studying the process, I see that during extraction, there are really a few things going on. The hot water must absorb, soften and break down and open up the coffee grounds cellulose structure, and expose the solids that can be extracted (dissolved). During this process, trapped CO2 gets released. Then, hot water must begin to dissolve the dissolvable solids at the right rate, and then the entire solution and dissolving process needs to be terminated at the right point by removing the solution, reducing the brew temperature, or both.
Pre-infusion kick starts the cellulose absorption stage without starting the dissolving stage. Even if you use hot water, the equal mass of both the water and ambient temperature grounds has a small amount of leftover water and fairly low (about 110°F) thermal energy that it doesn't count as extraction time.
Fascinating, this brew process, huh?
An 8/19/2012 update:
Learned a lot since this post. Cool brew water still dissolves coffee (an example of falsifying my own hypothesis).
Absorption holds solution in the grounds, and it turns out that it DOES participate as a solvent. I went through and verified that putting in about 2 times the coffee mass for brew water at ~70°F ends up with a very strong, underextracted coffee.
Example: 25g coffee, add room temperature 50g of water, allow to steep for a minute and then press. You get about 7-10g of very strong, underextracted tasting coffee - low bitterness, tea-like quality - strength a bit more than 6% or so but extraction very low. E = (S*R)/(1-S) = about 12-13% extraction using immersion calculation.
What gets extracted is probably important, as well as what it does for bloom. Used for bloom suppression, it works very well. The added cooler mass of the water lowers the mixed initial brew slurry temperature lower than the strike temperature than it would if all of the water was hot. Cooler temperatures for brewing in my experience tend to not have bitter taste, and at this date I suspect this is due to what gets extracted (or in the case of lipids, emulsified) for given temperatures.
Since I don't (yet) own equipment to do my own chromotagraphy, I'm guessing at what these compounds may be - but I experience significant bitterness when my strike temperatures exceed 205°F, and hypothesize that the higher temperatures are probably dissolving or emulsifying some compound or compounds that contribute to bitterness in the cup.
The learning continues.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
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